Winterize Your Sprinkler System in 3 Steps and Avoid Old Man Winter’s Wrath

Dawn M. Smith
Written by Dawn M. Smith
Updated February 18, 2022
Automatic sprinkler system
Photo: georgeclerk / E+ / Getty Images

Winterize your sprinkler system and put cracked and broken lines on ice

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The last thing you want to deal with when curled up on the couch, binging holiday movies, is a busted sprinkler system. Before you settle in for a long winter’s nap (or, however you plan to spend the frigid months) be sure to add winterizing your sprinkler system to your list. You’ll be glad you did once you’re six seasons deep during the coldest season.

  • Difficulty score: 2/5

  • Time needed: One to two hours

  • List of tools and materials: safety glasses, gloves, replacement sprinkler valves (if needed), pliers, foam insulating tape, and foam covers

Properly draining your irrigation system prevents cracks and broken lines from water expansion in the piping and valves over the cold months. For a carefree fall and winter, and an all-systems go-spring and summer, make sure you drain the system before temperatures dip to 30 degrees Fahrenheit.

Before you start prepping to winterize your irrigation system, dig out any manual or set of instructions that specifically details your sprinkler system. They’ll highlight winterization tips and tricks you haven’t thought about since installation. If the instructions went out with the recycling, try a quick internet search for your brand.

When to Consider Professional Sprinkler Winterization Services

It’s a smart idea to consider hiring a local professional landscaping company or plumber to winterize your sprinkler system because it’s an affordable, once-a-year fee for peace of mind. The maintenance costs between $50 to $120 for a home with one to six sprinkler zones

If freeze damage occurs, you’ll need a professional to repair the sprinkler system, which costs far more than preventative maintenance. Plumbers usually charge about $50 to $100 per hour plus the cost of parts. Remember Ben Franklin’s famous adage, “An ounce of prevention is worth a pound of cure?” It’s spot-on for your irrigation system needs. 

For the cost of your time and maybe some insulation products, you can drain the system yourself, especially if you have a manual or automatic system. However, exactly how you’ll do it depends on what kind of system you have. Your blow-out sprinkler system needs a local sprinkler professional with repair and winterization experience, especially if you’re not completely comfortable working with a high-powered air compressor.

1. Turn Off the Main Water and the Timer to Your Sprinkler System

Luckily the first step is an easy one: Just shut off the water supply to the irrigation system. It might be near your water meter. If you have a backflow preventer or check valves (you’re probably looking for two in your green irrigation system box), shut those off as well. Note that not all systems have backflow valves. 

If you have an automatic system, shut off the controller/timer using the “off” or “rain mode” setting. This shuts down the signal to the system, and thankfully, it keeps your programmed settings like the start time, valve run times, and clock. 

Come spring, just shut off the rain mode, and all should be good to go. To save a little bit of energy (about a night light’s worth) you could just shut off the power to the controller, but you’ll lose the settings you worked so hard to perfect. 

As an extra precaution, if your controller activates a pump, detach the wires connected to “MV” and “common.” This prevents the chance of the pump’s accidental activation, which could cause overheating.

2. Drain Your Irrigation System

Sprinkler in garden
Photo: Mykola Sosiukin / iStock / Getty Images

Remember, the water in your sprinkler system is pressurized, so wear eye protection during the draining process. 

It’s not enough to simply turn off the main water flow; the trapped water is damage waiting to happen. It might take a little while, but you have to empty as much water as possible from the system to avoid a massive mess once the temperatures warm up. 

Before you can start the draining process, you need to know which kind of irrigation system you have to choose from three draining methods: manual drain, automatic drain, or compressed air blow-out drain. Check the sprinkler system guide you foundat the bottom of the junk drawer for more info.

Manual Draining

Most manual drain systems have shut-off valves at the end of the piping. Slowly open the valves, one by one, to release the water. If you have check valves, go ahead and drain those too. Raising your sprinkler heads drains more water. Close all of the valves when done. Easy enough.

Automatic Draining

For those with automatic draining systems, the water drains after the main valve is closed and the water pressure decreases. To start the process, open one of the sprinkler heads to relieve some pressure and begin clearing the pipes. 

Most of the water will drain, but you’ll also need to empty the water from inside the check valves. There’s a plastic cap with wire sprouting out, called a solenoid, on each valve. Loosen the cap to increase the airflow and let more water out. If your system has a backflow device, you’ll also need to drain the water between it and the shut-off valve.

Blow-Out Draining

Of all the draining systems, professionals highly recommend hiring a local sprinkler winterization company to take care of systems that need blow-out draining once a year. The method uses an air compressor attached to your system to force the remaining water through the pipes and out of the sprinkler heads.  

DIYers can cause plenty of damage to their irrigation system and themselves if not done correctly. Take a look at some of the potential problems you’ll want to avoid.

  • Not all sprinkler systems can handle the intense air pressure a commercial compressor  emits. If it’s too strong, your pipe system will suffer damage.

  • The typical air compressor a homeowner has isn’t powerful enough to completely empty the system. You need an 80 to 100 cubic feet per minute (CFM) pressure supply to do the job right.

  • Any water left behind has the potential to freeze and damage the system.

  • Homeowners without experience handling this amount of pressure might face serious injury.

3. Add Insulation to Sprinkler System Parts Above Ground

The last thing you’ll want to do during a streak of frigid temperatures is work on your sprinkler system. Before the threat of freezing temps, take the time to insulate the irrigation system components exposed to cold weather. This is best to tackle after the summer growing season is over and before fall gets into full swing.

Get familiar with the aisle at the hardware store that has various insulation tape and foam covers. You’ll need enough to wrap the main shut-off, any exposed pipes, and backflow preventers (don’t block air vents or drain outlets). If it makes sense in your yard, use pine straw to cover the system for added warmth and camouflage the sprinkler system’s visible parts.   

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